1. Field of the Invention
The present invention relates to a method and apparatus for implementing high-resolution print modes, and, more particularly, to a method and apparatus for improving text print quality of an imaging device in high-resolution print mode.
2. Description of the Related Art
Techniques for obtaining high resolution printing are used to take print data that is available at one resolution and translate that data to another resolution. The translating process from one resolution to another resolution is known as scaling. Once an image is scaled a technique is used to determine the intensity of the printing medium and the positioning of the printing medium. Such a technique is generally known as a half-toning technique. For example, if the printing medium is ink, the intensity of the ink dot and the placement of the ink dot is determined by the half-toning technique.
Half-toning techniques or algorithms include error diffusion algorithms and ordered dither techniques, which represent techniques for breaking a continuous tone image into a dot structure suitable for printing ink on paper. Error diffusion produces a very finely dispersed dot structure, which is particularly well suited for use in ink jet printers. One of the early error diffusion algorithms was invented by Floyd N. Steinberg in 1975 and is still considered a valuable contribution to the art. However many error diffusion algorithms produce visually noticeable artifacts as a result of the dot placement choices inherent in half-toning algorithms.
Some of the problems of error diffusion algorithms are that they contain a number of inherent drawbacks; for example, patches of regular structure may appear close to certain intensity levels. Such patches are visually disturbing, but also the uneven transition between a structured and unstructured area are clearly visible and undesirable. Some question whether error diffusion algorithms can even be used for certain printing purposes. Some methods used to overcome drawbacks of error diffusion techniques include using serpentine paths instead of scan lines or using space filling curves as the path for processing the intensity level of dot placement. Such techniques have a tendency to improve the behavior for dot placement for some intensity levels and worsening it for others.
What is needed in the art is a method for producing high quality text while in a high-resolution print mode.